Diggingthe1 is correct... the engraved letters are definitely WAL. That particular version of "ornate" lettering was popular in the 1880s through very-early 1900s. (You'll see it on quite a few buttons for post-civil-war organizations in the Albert button-book.) I've never seen any mention of the Scovill Company doing engraving, so in my opinion this one is most likely a "personalized" ball-button. I suspect the WAL engraving is more likely to be the owner's initials, rather than representing an Organization's name.
Sidenote:
When you see three initials on a button, and one of the letters is an S, it's very often the initials of a school. Similarly, a letter A often stood for Academy, and C for College. See the Albert button-book's section title Schools & Universities.